N/A power 5sfe at its best? Options

[Theshanon]

so i searched online for info in terms of the 5sfe motor and i decided to stick to building this rather then swaping out. but check this http://warp.scl.utah.edu/mr2/200rwhp5sfe.html i'm pretty sure some have you have come across this but what do you think?

[presure2]

mrt is an active member of mr2oc and celicatech.
hes no where near 200whp.
its all just "theory", that he is slowly working on.

if you want a 200whp 5sfe, n/a is not the way to go.

[Theshanon]

haahha i was wanting your reply soooo bad, i even wanted to put as the commnet "pressure2, this one is for you" haha

[crandsberry]

That guy has got pretty good intuition, but come on.. HP= (Trq*rpm)/5252 is waay too basic to work from.

Why not just take a Hemi V8 that make 400 foot-pounds of torque and tune it to rev to 10,000 rpm, you'd make 700 horsepower without boost! woot!



You need to look at the laws of fluid motion.
The dificulty with natually asparated is: at high rpm, the piston travles downward much faster than the fuel/air mixtur can fill the cylinder.

The faster you can fill the cylinders, the more horsepower you get.

The biggest trick builders use to overcome this is maximizing that sweet spot called "valve overlap," which means opening the intake valve while the exhaust vale is still closing. This allows more air to be forced in before the intake stroke even begins.
Now this works beautifully if the valves are far apart on opposite side of the combustion chamber, as the exhaust leaves it even helps pull in more air.

Now enter the 5SFE head, those valves are right on top of each other. Only 15 degrees of separation. Ever tried to rush into an elevator while a bunch of people are trying to leave the elvator? basically what would happen if you tried valve overlap on the 5S . Toyota knew this, thats why the intake and exhaust cams are permanenlty locked together with gears.

So no... 200whp at 8000rpm is not happening.. ever

But dont lose heart, listen to pressure2, since the atomospheric pressure is too weak, just add you own
bbbbbboooooost


haha its long, dont judge me, im a mech. engineering major and i was bored

[Theshanon]

hahah just wanted to see some respones based on this theory, i'm planning on boosting if anything, but time is a must =)

[Kwanza26]

That guy has got pretty good intuition, but come on.. HP= (Trq*rpm)/5252 is waay too basic to work from.

Why not just take a Hemi V8 that make 400 foot-pounds of torque and tune it to rev to 10,000 rpm, you'd make 700 horsepower without boost! woot!

haha its long, dont judge me, im a mech. engineering major and i was bored

Being a mechanical engineering major... you're still over simplifying things...

The MOST MAJOR IMPORTANT THING!!! Piston speed. As mentioned above by the mech. engineer... the only way to make additional power is to fill the cylinders faster either by forced induction OR revving. Even assuming the 5SFE head has good enough flow characteristics to make top-end power (which it probably can with significant modifications)... the bottom-end is still the weak spot in making n/a power because of piston speed. With most long stroke motors, the speed of the piston at say 7000 rpms is typically equivalent to a short stroke motor (4AG for example) at say 9,000 rpms. Basically, in addition to building the top-end to increase overall flow to the point it can make 200whp... you still have the problem of the long stroke and the inability of the bottom-end to sustain high revolutions.

This is the MAIN reason why I think it's silly to think "5SGE" or n/a "5SFE". The 5S block is designed to do exactly opposite of what a high-powered n/a motor is supposed to do. Rev.

[crandsberry]

The MOST MAJOR IMPORTANT THING!!! Piston speed.

Good call kwanza, lol i definitly should have mentioned that, piston speed creates a complete barrier in terms of tweaking the redline. Guess thats why you hear about these high horsepower Formula one engines with a nice wide bore, but a rediculously short stroke.

Maybe we need to look to the old toytota R series engines, and see how they coaxed horsepower out of them. The blocks have a little more displacement, but they suffer from the same 90mm of stroke that the 5S does, and were run for many succesful years of circiut racing in the late 80s in the old celicas.

Granted they were truck engines, and the bottem assembly was bulletproof.
http://www.toysport.com/Technical%20Inform..._tech_notes.htm